Introduction: Anterior cervical discectomy and fusion (ACDF) using stand-alone synthetic PEEK (polyetheretherketone) cage is an effective and safe for one-level degenerative cervical disease. However, anteriorly developed subsidence of fusion site may result in severe kyphotic deformity. The purpose of this study is to evaluate the risk factors of large anterior subsidence after ACDF using a stand-alone cage and the changes of overall cervical alignment by performing a radiological analysis.
Methods: This study included 80 patients, who underwent anterior cervical fusion using stand-alone PEEK cage and DBM (demineralized bone matrix) in single level degenerative cervical disease between January 2006 and December 2010. For the radiologic parameters, anterior height (AH) and posterior height (PH) of fusion segment, segmental angle (SA) of fusion level, and overall C2-C7 angle (cervical sagittal angle, CSA) were assessed. The percent of cage length to antero-posterior (AP) body length was measured. Cage height, location and species were also assessed.
Results: The average follow up period was 26.7 months. Patients with large anterior subsidence had a positive correlation with posterior located cage, or lordotic cage (p < 0.05). Percent of cage length to antero-posterior body length was also associated with large anterior subsidence (p < 0.05). In sagittal alignment, SA was significantly decreased in group A at the last follow-up (p < 0.05). However, there was no significant difference of CSA between two groups at the last follow-up period. In clinical outcomes, there were no significant differences of VAS and JOA between two groups.
Conclusions: Despite some subsidence, ACDF using stand-alone PEEK cage with DBM is a safe and reliable surgical treatment option in single-level degenerative cervical disease. However, anterior subsidence was largely developed compared to posterior subsidence in cases with posterior located cage, lordotic cage, or low percent of cage length to AP body length.
Patient Care: Long term clinical outcome
Learning Objectives: Anterior subsidence negative effect